Oscillating convective airflow in a vented cavity with a heated immersed body. Influence of the heating intensity

The influence of the air variable properties on the buoyancy-driven airflows established in vented square cavities with an inner heated body is numerically investigated. Two-dimensional, unsteady, and turbulent simulations are obtained, considering uniform wall temperature heating conditions. The low-Reynolds k − ω turbulence model is employed. The average Nusselt number and the dimensionless mass-flow rate are obtained for a range of the Rayleigh number varying from 104 to 1012. The results obtained for different heating intensities are analyzed and compared. The conditions under which the flow becomes clearly transient, giving rise to an oscillatory solution, are determined. The dimensionless oscillating period of the transient Nusselt number exhibits a logarithmic decay as a function of the Rayleigh number. The structure of the flow into the cavity as a function of time, are shown.